Streamflow Statistics for Monroe County, Pennsylvania

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Streamflow Statistics for the Paradise and Pocono Creek Watersheds and Selected Streamflow-Gaging Stations in Monroe County, Pennsylvania by Ronald E. Thompson and Gregory J. Cavallo

In cooperation with the Delaware River Basin Commission and the Brodhead Watershed Association

Scientific Investigations Report 2005-5162

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary

U.S. Geological Survey P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2005

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Suggested citation: Thompson, R.E., and Cavallo, G.J., 2005, Streamflow statistics for the Paradise and Pocono Creek Watersheds and selected streamflow-gaging stations in Monroe County, Pennsylvania: U.S. Geological Survey Scientific Investi- gations Report 2005-5162, 21 p. iii

Contents

Abstract...... 1 Introduction ...... 1 Purpose and Scope ...... 1 Study Area...... 1 Hydrogeologic Setting ...... 1 Previous Investigations ...... 3 Continuous- and Partial-Record Stations ...... 3 Methods For Determining Streamflow Statistics at Continuous- and Partial-Record Stations...... 4 Streamflow Statistics for Monroe County, Pennsylvania ...... 6 Subbasin Yields in the Paradise and Pocono Creek Watersheds...... 6 Observed Streamflow Statistics for Continuous-Record Stations ...... 6 Predicted Streamflow Statistics for Partial-Record Stations ...... 6 Comparison of Predicted and Observed Streamflow Statistics for Continuous-Record Stations ...... 13 Regression Analyses of Continuous-Record Station Data ...... 13 Differences in Predicted and Observed Streamflow Statistics for Continuous-Record Stations...... 13 Limitations of the Investigation and Statistics ...... 19 Summary and Conclusions ...... 19 Acknowledgments ...... 19 Selected References...... 19

Figures

1. Map showing bedrock geology, Paradise and Pocono Creek watershed boundaries, and selected streamflow-gaging stations in Monroe County, Pennsylvania ...... 2 2. Graph showing concurrent daily mean flows at Brodhead Creek near Analomink, Pa., and intermittent measurements at Pocono Creek near Stroudsburg, Pa...... 5 3. Graph showing log 10-transformed concurrent daily mean flows at Brodhead Creek near Analomink, Pa., and intermittent measurements at Pocono Creek near Stroudsburg, Pa...... 5 4. Map showing bedrock geology and base-flow measurement locations in the Paradise and Pocono Creek watersheds, Monroe County, Pennsylvania...... 7 5. Graph showing observed and predicted streamflow statistics for Lehigh River at Stoddartsville, Pa...... 13 iv

Tables

1. Selected continuous- and partial-record stations in Monroe County, Pennsylvania...... 4 2. Locations in downstream order, base flows measured, and subbasin yields for the Paradise and Pocono Creek watersheds, Monroe County, Pennsylvania: October 25-27, 2000; May 2-3, 2001; and July 8-9, 2003...... 8 3. Observed streamflow statistics for continuous-record stations in Monroe County, Pennsylvania...... 11 4. Regression coefficients and equations for predicting 7-day, low-flow recurrence-interval statistics at partial-record stations in Monroe County, Pennsylvania...... 12 5. Predicted streamflow statistics for partial-record stations in Monroe County, Pennsylvania...... 14 6. Regression coefficients and equations for predicting 7-day, low-flow recurrence-interval statistics at continuous-record stations (treated as partial-record stations) in Monroe County, Pennsylvania...... 16 7. Predicted streamflow statistics and percent differences from observed statistics for continuous-record stations in Monroe County, Pennsylvania...... 17

Conversion Factors and Datum

Multiply By To obtain Length inch (in.) 2.54 centimeter (cm) foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) Area square mile (mi2) 259.0 hectare (ha) square mile (mi2) 2.590 square kilometer (km2) Flow rate cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) cubic foot per second per square mile cubic meter per second per square [(ft3/s)/mi2] 0.01093 kilometer [(m3/s)/km2] cubic foot per second per square mile million gallons per day per square mile [(ft3/s)/mi2] 0.6463 [(Mgal/d)/mi2]

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27).

Temperature in degrees Fahrenheit (˚F) may be converted to degrees Celsius (˚C) as follows:

˚C = (˚F - 32) / 1.8 Streamflow Statistics for the Paradise and Pocono Creek Watersheds and Selected Streamflow-Gaging Stations in Monroe County, Pennsylvania by Ronald E. Thompson and Gregory J. Cavallo

Abstract agement area outlets (pour points) and to determine stream reaches that are gaining or losing flow. A suite of 36 observed streamflow statistics, ranging from high to low flows, were computed for 7 continuous-record and Purpose and Scope predicted for 12 partial-record streamflow-gaging stations in Monroe County, Pa. The predicted statistics for the partial- This report presents observed and predicted streamflow record stations were determined from regression analyses of statistics for selected streamflow-gaging stations (stations) in intermittent streamflow measurements made at the partial- Monroe County, Pa., and subbasin yields for the Paradise and record stations and concurrent daily mean flows at index con- Pocono Creek watersheds. The report also discusses the meth- tinuous-record stations. The prediction methodology has been ods used to determine the streamflow statistics, an analysis of previously used only for estimating low-flow statistics. Results the prediction methodology, and limitations of the methods and from this study indicate the methodology may have applicabil- the statistics. Thirty-six streamflow statistics were computed ity for predicting high- and intermediate-flow statistics as well. for 7 continuous-record stations and predicted for 12 partial- Three sets of base-flow measurements were made at 40 sites in record stations. The statistics computed at the continuous- the Paradise and Pocono Creek watersheds to determine subba- record stations are referred to as “observed” in this report. Sub- sin yields and stream reaches gaining or losing flow. Subbasin basin yields were determined at 29 sites in the Pocono Creek yields, the base-flow measurements normalized to respective watershed during 2000 and 2001 and at 11 sites in the Paradise drainage areas, were consistent for each measurement period. Creek watershed during 2003.

Introduction Study Area Monroe County is in the Pocono Mountains area of north- The Delaware River Basin Commission (DRBC) has eastern Pennsylvania and, for the period 1931-2000, had an established a “Goal-Based Planning Approach” targeted for use average annual temperature of 47°F and average annual precip- by watershed groups in the basin. These groups are starting or itation of 44 in. (National Climatic Data Center, 2002). Average have started an inventory of water resources and will use the annual potential evaporation ranges from 25 to 27 in. (Flippo, inventory as part of a comprehensive process for planning 1982a). development. The U.S. Geological Survey (USGS), the DRBC, The Lehigh River flows along the northwestern boundary and the Brodhead Watershed Association cooperated in a study of the county, and the Delaware River is part of the southeastern to determine streamflow statistics in the Paradise and Pocono boundary. The Borough of Stroudsburg, on the south-central Creek watersheds and surrounding parts of Monroe County, Pa. boundary, is the county seat. Paradise and Pocono Creeks, The technical information developed for this study will help which flow in an easterly direction and share a common water- form a basis for evaluating the effects of competing water uses shed divide, are tributaries to Brodhead Creek, which flows in on water quantity in the Pocono and Paradise Creek watersheds a southerly direction (fig. 1). and other parts of Monroe County. The Pocono Creek watershed planning effort served as a pilot project for the DRBC approach, and the Paradise Creek watershed planning effort is Hydrogeologic Setting following the same process. Streamflow statistics are needed in Monroe County to quantify surface-water resources and to The surficial geology in Monroe County includes glacial serve as input for ground-water models. Subbasin yields for the deposits, sandstones, conglomerates, siltstones, shales, and Paradise and Pocono Creek watersheds also are needed at man- small amounts of carbonate rock that have been deformed by 2 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania

Figure 1. Bedrock geology, Paradise and Pocono Creek watershed boundaries, and selected streamflow-gaging stations in Monroe County, Pennsylvania Introduction 3 intense folding in the southeastern third of the county and gentle tistic(s) from the continuous-record station (U.S. Geological folding throughout the remainder of the county. Parts of the Survey, 2002). Upper, Middle, and Lower Series of the Devonian System are A second approach used graphical correlation analysis of all exposed in the landscape. Carswell and Lloyd (1979) identi- intermittent measurements at partial-record stations and con- fied the Duncannon, Poplar Gap, Packerton, Long Run, Beaver- current daily mean flows at nearby continuous-record stations dam Run, Walcksville, and Towamensing Members of the to predict low-flow statistics at partial-record stations. For Catskill Formation, which makes up approximately two-thirds Pennsylvania streams, that method was exemplified in Busch of the exposed bedrock. The remaining third includes the Trim- and Shaw (1966), who used procedures discussed by Searcy mers Rock Formation and parts of the Hamilton and Oriskany (1960). Page and Shaw (1977) updated the Busch and Shaw Groups, as well as other undifferentiated Devonian and Silurian results using procedures discussed by Riggs (1972). Hardison rocks (fig. 1). These bedrock units generally have low primary and Moss (1972) reviewed statistics predicted by correlation of porosity and permeability; however, post-depositional defor- base-flow measurements and concurrent daily mean flows and mation and fracturing have increased secondary permeability. discussed the accuracy of the predicted low-flow statistics. Deformation also has produced synclines and anticlines that A third approach has been regression-based modeling. provide preferential pathways for ground-water flow. Riggs (1973) discussed multiple regression using low-flow sta- During the Pleistocene Epoch, as many as four separate tistics as predicted values and basin characteristics (for exam- periods of glaciation covered most of the county (Epstein and ple, drainage area) as explanatory variables. Hardison (1971) others, 1974) and left unconsolidated deposits of clay, silt, sand, presented an analysis of regression error for predicted statistics gravel, cobbles, and boulders up to approximately 100-ft thick at ungaged sites. Tasker (U.S. Geological Survey, written com- in the stream valleys of Monroe County (R.A. Sloto, U.S. Geo- mun., 1978) expanded on Hardison (1971) by describing the logical Survey, oral commun., 2004). Areas where porous gla- relation of standard errors in logarithmic units and standard cial deposits are connected to the water table typically yield errors in percent. Stedinger and Thomas (1985) proposed an higher stream base flows per unit of drainage area during dry alternative approach using linear regression of intermittent periods than nonglaciated parts of Pennsylvania. measurements at partial-record stations and concurrent daily mean flows at continuous-record stations to generate an unbi- ased estimator with minimum mean square error for predicting Previous Investigations low-flow recurrence-interval statistics at the partial-record stations. Wilson (2000) evaluated the Stedinger and Thomas White and Sloto (1990) computed 2-, 5-, 10-, 25-, 50-, and (1985) approach using combinations of continuous-record sta- 100-year recurrence-interval base flows for 309 stations in tions in Indiana. Wilson found the most accurate and least vari- Pennsylvania and on the Delaware River in New York and New able results were produced when two index stations on the same Jersey. Schreffler (1998) used the Maintenance of Variance stream or tributaries of the partial-record station were used. Extension, Type 1 (MOVE1) technique (Hirsch, 1982) to pre- Regression-based modeling that follows the Stedinger and Tho- dict low-flow and harmonic mean statistics at 34 partial-record mas (1985) methodology is the approach used in this study to stations in Chester County, Pa. Ehlke and Reed (1999) com- predict streamflow statistics. pared methods for predicting streamflow statistics for Pennsyl- vania streams. They found the 7-day, 10-year low flow com- Continuous- and Partial-Record Stations puted using a log-Pearson, Type III distribution (Riggs, 1968b) and the regression of basin characteristics method presented in Continuous-record stations record gage height of the Flippo (1982b) differed significantly only for about 7 percent of stream water surface (stage) continuously or at small time inter- Pennsylvania, although the same methods produced 50- and vals, such as 15 minutes. Stations are connected to the streams 100-year flood predictions that differed significantly for through intake pipes or other stage-sensing devices, such as 24 percent of the State. Senior and Koerkle (2003) simulated pressure transducers. Stage-flow relations are established by flows in the Christina River Basin, Pennsylvania, Maryland, making flow measurements at different stages, and daily mean and Delaware, using Hydrologic Simulation Program-Fortran flows are computed using the stage records and stage-flow rela- (HSPF) software (Donigian and others, 1984) and found annual tions. differences between observed and simulated values ranging Little or no stage data are collected at partial-record sta- from -6.9 to 6.5 percent and an overall error for a 4-year period tions. The primary data collected at these stations are intermit- of -1.1 percent. tent measurements of flow made over multiple years. Some par- Other approaches have been used to predict low-flow sta- tial-record stations are operated specifically to obtain low-flow tistics at locations without daily mean flow data. One approach data; others are used to obtain measurements over a wide range has been to determine drainage area of the location, divide it by of flows. the drainage area of a nearby, hydrologically similar, continu- Information about the continuous- and partial-record sta- ous-record station with statistics computed from daily mean tions used for analyses is shown in table 1, and their locations flow data, and multiply the area-ratio result by the needed sta- are mapped on figure 1. Drainage areas for the stations range in 4 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania

size from 259 to 2.39 mi2. Continuous-record stations with tics, the daily mean flow data obtained from NWISWeb were short periods of daily mean flows were analyzed as partial- first processed using the local-minimum option in the record stations for this study and are identified in table 1. Hydrograph Separation Program (HYSEP) software developed by Sloto (1988), and the resulting daily mean base-flow data Methods for Determining Streamflow Statistics at were then processed using SWSTAT. Continuous- and Partial-Record Stations The procedure for obtaining predicted statistics for the partial-record stations started with a plotting and correlation pro- Observed streamflow statistics for the continuous-record cess developed in the USGS Pennsylvania Water Science Cen- stations were computed from daily mean flows retrieved from ter (E.H. Koerkle, U.S. Geological Survey, written commun., USGS databases. The observed statistics include mean monthly 2004). The process plotted intermittent measurements made at flows, mean annual flow, 7-day low flows for 4 recurrence the 12 partial-record stations on 4-day daily mean flow hydro- intervals, 13 flow durations, mean annual base flow, and base graphs preceding the measurements for the 7 continuous-record flows for 5 recurrence intervals. The mean monthly and the stations being tested as index stations. The plotting aspect mean annual flow statistics were obtained from Durlin and allowed acceptance or elimination of each measurement based Schaffstall (1997, 2004). To determine the 7-day low-flow recurrence-interval and flow-duration statistics, daily mean on whether the continuous-record stations being tested flow data were obtained from NWISWeb data for Pennsylvania appeared to be in a base-flow regime. After all measurements (U.S. Geological Survey, 2004) and processed using Surface- and associated hydrographs were reviewed, the process pro- Water Statistics (SWSTAT) software (Flynn and others, 1995). duced a correlation coefficient (r) for each continuous- and par- To determine the annual base-flow recurrence-interval statis- tial-record station relation. Only those relations with r values

Table 1. Selected continuous- and partial-record stations in Monroe County, Pennsylvania.

[Horizontal datum is North American Datum of 1927; mi2, square miles; Station type: C, continuous-record station; P, partial-record station with intermittent streamﬂow measurements; C-P, short continuous record used as a partial record for this report; Period of station record is the time span operated as a continuous- record and/or partial-record station—no ending date indicates station in operation through 2003]

U.S. Geological Location Latitude Longitude Drainage Period of Survey station Station Station description number in (decimal (decimal area station identification type figure 1 degrees) degrees) (mi2) record number 01439500 Bush Kill at Shoemakers, Pa. 1 41.088056 75.038056 117 C 1908Ð 01440250 Shawnee Creek at Shawnee, Pa. 2 41.011667 75.111111 4.58 P 1970Ð1973 01440272 Buck Hill Creek at Buck Hill Falls, Pa. 3 41.191944 75.286944 5.76 P 1977Ð1980 01440300 Mill Creek at Mountainhome, Pa. 4 41.163889 75.266667 5.84 P 1960Ð1999 01440400 Brodhead Creek near Analomink, Pa. 5 41.084722 75.215000 65.9 C 1957Ð 01440485 Swiftwater Creek at Swiftwater, Pa. 6 41.093889 75.322500 6.59 C-P 2001Ð 01440500 Paradise Creek at Henryville, Pa. 7 41.100000 75.251389 30.2 P 1965Ð1991 01440800 Kettle Creek at Snydersville, Pa. 8 40.958333 75.293611 5.28 P 1944Ð1957 01441000 McMichael Creek near Stroudsburg, Pa. 9 40.979167 75.201389 65.3 P 1970Ð1991 01441495 Pocono Creek above Wigwam Run near 10 40.990833 75.255556 38.9 C-P 2002Ð Stroudsburg, Pa. 01441500 Pocono Creek near Stroudsburg, Pa. 11 40.986111 75.226389 41.0 C-P 1932Ð2001 01442500 Brodhead Creek at Minisink Hills, Pa. 12 40.998611 75.143056 259 C 1950Ð 01442600 Marshall Creek at Minisink Hills, Pa. 13 40.998056 75.142078 27.1 P 1958Ð1991 01442700 Cherry Creek at Delaware Water Gap, Pa. 14 40.979167 75.161111 19.3 P 1958Ð1968 01447500 Lehigh River at Stoddartsville, Pa. 15 41.130278 75.625833 91.7 C 1943Ð 01447680 Tunkhannock Creek near Long Pond, Pa. 16 41.065278 75.520556 20.0 C 1965Ð 01448500 Dilldown Creek near Long Pond, Pa. 17 41.035556 75.543611 2.39 C 1948Ð1996 01449355 Middle Creek at Kresgeville, Pa. 18 40.900833 75.497222 18.6 P 1970Ð1991 01449360 Pohopoco Creek at Kresgeville, Pa. 19 40.897500 75.502778 49.9 C 1966Ð Introduction 5 equal to or greater than 0.70 were retained for further analyses (Stedinger and Thomas, 1985). Although 2 of the 12 partial- record stations used in this study had only 6 suitable measurements, instead of a minimum of 10 as recommended by Ste- dinger and Thomas (1985), those two stations had good relations with the respective index gage and were included to increase geographic coverage. The other 10 partial-record stations had 10 or more such measurements. All the retained relations of partial-record station measurements and continuous-record station concurrent daily mean flows were plotted for visual examination. Concurrent daily mean flow data for Brodhead Creek near Analomink (an index station) and intermittent measurements made at Pocono Creek near Stroudsburg (a partial-record station) are shown as an Figure 3. Log 10-transformed concurrent daily mean flows at example (fig. 2). The data appear linear, but non-constant vari- Brodhead Creek near Analomink, Pa., and intermittent measure- ance from a line of best fit is evident in the funnel-shaped plot ments at Pocono Creek near Stroudsburg, Pa. as the concurrent daily means and intermittent measurements increase in magnitude. Non-constant variance, which also occurred in the other relation plots, violates the assumption of Regression analyses were then conducted on transformed constant variance inherent in parametric regression (Helsel and data using Generalized Least Squares-Network Analysis (GLS- Hirsch, 1992). NET) software (Tasker and Stedlinger, 1989). The analyses of the daily mean flows for the seven continuous-record stations being tested as indexes and the measurements at each partial- record station took the form

LogQP = A + bLogQC1 + cLogQC2 + dLogQC3 + eLogQC4 + fLogQC5 + gLogQC6 + hLogQC7, (1)

where Log is the base 10 logarithm, QP is an intermittent flow measurement at a partial- record station, A is the intercept, QC1 is the concurrent daily mean for Bush Kill at Shoemakers, Figure 2. Concurrent daily mean flows at Brodhead Creek near QC2 is the concurrent daily mean for Brodhead Creek Analomink, Pa., and intermittent measurements at Pocono Creek near Analomink, near Stroudsburg, Pa. QC3 is the concurrent daily mean for Brodhead Creek at Minisink Hills, QC4 is the concurrent daily mean for Lehigh River at The data were log 10-transformed and re-plotted to see if Stoddartsville, the non-constant variance could be removed for further analy- QC5 is the concurrent daily mean for Tunkhannock ses. An example plot is shown in figure 3, which contains trans- Creek near Long Pond, formed data from figure 2 and a line of best fit. Transforming QC6 is the concurrent daily mean for Dilldown Creek the data eliminated non-constant variance from the relation near Long Pond, between Brodhead Creek near Analomink and Pocono Creek QC7 is the concurrent daily mean for Pohopoco Creek near Stroudsburg, as well as measured flows at the partial- at Kresgeville, and record stations and concurrent daily mean flows at the respec- b, c, d, e, f, g, and h are regression coefficients specific tive index stations in the other correlations. to each partial-record station.

Determining relative subbasin yields for the Paradise and Pocono Creek watersheds was accomplished by making 3 sets of base-flow measurements at 40 locations. The measured flows were then divided by the respective drainage areas of the locations to arrive at the subbasin yields during the time periods when the measurements were made. 6 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania

Streamflow Statistics for Monroe County, above the confluence with Pocono Creek probably indicates flow interception by subsurface drains associated with the Inter- Pennsylvania state 80 corridor upstream from the measurement site. Other exceptions are the maximum yield and the low Stream reaches with possible gains or losses in flow were yields from three subbasins in the Paradise Creek watershed determined by analyzing the subbasin yields in downstream during the July 7-8, 2003, period. The 2.73-ft3/s/mi2 yield for order. Observed statistics for continuous-record stations and Swiftwater Creek at Swiftwater probably reflects surface-water predicted statistics for partial-record stations in Monroe discharges from treatment facilities upstream. However, the County, when combined with the subbasin yields, provided an effect on yields in the main stem of Paradise Creek diminished encapsulation of the surface-water resources in the county. downstream. The low yields of 1.06 ft3/s/mi2 for Cranberry Creek and 0.71 ft3/s/mi2 for Butz Run likely reflect the rela- Subbasin Yields in the Paradise and Pocono Creek tively flat gradient of those two subbasins and a bog-like effect Watersheds that would be manifested as relatively low yields during intermediate base flows, as occurred during the measurements, and Base flows in the Paradise and Pocono Creek watersheds high base flows and relatively high yields during low base were measured during low- and intermediate-flow regimes flows. based on indexed flow in Brodhead Creek. The flow in Brod- head Creek near Analomink, an index station, during the Octo- ber 25-27, 2000, measurements in the Pocono Creek watershed Observed Streamflow Statistics for Continuous- was at a rate equaled or exceeded about 85 percent of the time, Record Stations a low-flow regime. During the May 2-3, 2001, measurements in the Pocono Creek watershed and the July 8-9, 2003, measure- The observed statistics for the seven continuous-record ments in the Paradise Creek watershed, the Analomink station stations in Monroe County are shown in table 3. The range was at a rate equaled or exceeded about 50 percent of the time, between the maximum and minimum statistics for each station, an intermediate-flow regime. Some of the measurements were as exemplified by 1,270 ft3/s (1 percent chance of being equaled made at locations identified by the planning groups as manage- or exceeded, D1) and 5.8 ft3/s (lowest average flow expected ment area pour points. Other locations were selected to evaluate for 7 consecutive days every 20 years, Q7,20) for Bush Kill at reaches for possible gains and losses in flow and to cover a range of geographic areas and drainage-area sizes. The loca- Shoemakers, reflects the large absolute differences in the tions of the base-flow measurement sites are mapped in observed statistics for each station. The range in flows equaled figure 4. or exceeded 1 percent of the time for all seven stations (from 3 Subbasin yields in the Paradise and Pocono Creek water- 3,410 to 32 ft /s) reflects the two orders of magnitude range in 2 sheds are shown in table 2. During Oct. 25-27, 2000, a reach of drainage areas (from 259 to 2.39 mi ). the Pocono Creek between Sullivan Trail and above State Route 715 at Tannersville showed a loss in yield from 0.54 to 0.38 ft3/s/mi2 (table 2). A similar loss was measured during Predicted Streamflow Statistics for Partial-Record May 2-3, 2001, when the yields dropped from 1.33 to Stations 1.03 ft3/s/mi2 in the same reach. These losses may indicate a low yield from the Scot Run subbasin, which is a tributary in The 7-day, low-flow regression coefficients and resulting that reach; a natural geohydrologic effect such as some part of equations for the seven continuous-record stations tested as the flow going underground over the reach; an anthropogenic index stations are shown in table 4. Although all continuous- effect, such as large ground-water withdrawals pulling flow record stations tested as index stations appeared in at least one from Pocono Creek; or other factors not observed during the partial-record station relation with a correlation coefficient (r) measurements. equal to or greater than 0.70 during the tests, the best relations The subbasin yields within the watersheds during each set (lowest standard errors and highest coefficients of determina- of measurements were relatively consistent. The consistency tion, R2) contained only four of the seven tested stations. An during each measurement period was reflected in standard devi- evaluation of the basin characteristics for the tested stations ations that were no more than one-third the magnitude of the means and in the close agreement between the means and medi- revealed no basis as to why three of the seven in table 4 were ans. Two exceptions are the maximum and minimum yields in not included in the best relations. Two of the partial-record sta- the Pocono Creek watershed during the October 25-27, 2000, tions had 2 index stations in the best relations. The remaining period. The 0.64 ft3/s/mi2 yield for Pocono Creek above the 10 partial-record stations had only 1 index station in the best confluence with Coolmoor Run probably reflects an increased relations. Ten of the relations had standard errors less than ground-water discharge effect from holding ponds upstream 31 percent and coefficients of determination (R2) greater than or from that location. The 0.11 ft3/s/mi2 yield for Wigwam Run equal to 0.90. Streamflow Statistics for Monroe County, Pennsylvania 7

41°10’30"

75°19’

Paradise Creek Watershed

2 1

7 8 3 75°24’30" 9 4 6 5 75°13’30"

41°05’ 12 10

11 14 21 15 13 16 20

17 18 19 22 23 25 Pocono Creek 24 Watershed 26 27 33 0 2 4 MILES 28 35 31 34 0 2 4 KILOMETERS 32 36 29 30 38 40°59’30" 37 39 Stroudsburg

Geology from Pennsylvania 40 PENNSYLVANIA Topographic and Geologic Survey

EXPLANATION CATSKILL FORMATION MEMBERS Poplar gap Packerton

Beaverdam Run, Long Run, and Walcksville

PARADISE AND POCONO Towamensing CREEK WATERSHEDS TRIMMERS ROCK FORMATION HAMILTON AND ORISKANY GROUPS, AND UNDIFFERENTIATED DEVONIAN AND SILURIAN ROCKS

4 BASE-FLOW MEASUREMENT LOCATION

Figure 4. Bedrock geology and base-flow measurement locations in the Paradise and Pocono Creek watersheds, Monroe County, Pennsylvania. 8 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania ) 2 /s/ 3 mi yield Sub- basin (ft /s) 3 (ft Base flow measured July 8-9, 2003 ment Paradise Creek locations Date of October 25-27, October measure- unty, Pennsylvania: ) 2 /s/ 3 mi yield Sub- basin (ft /s) 3 (ft Base flow measured May 2-3, 2001 Pocono Creek locations ment Date of measure- ) 2 /s/ 3 mi yield Sub- basin (ft , cubic feet per second per square mile; NA, not appropriate or indeterminable; --, no data] , cubic feet per second square mile; NA, 2 /s) 3 /s/mi 3 (ft Base flow measured October 25-27, 2000 Pocono Creek locations ment Date of measure- ) 2 /s, cubic feet per second; ft 3 area (mi Drainage 12 3.183 6.15 -- 13.9 --5 -- --6 -- -- 9.817 -- 10.2 -- --8 -- 4.77 -- --9 -- 15.0 ------7.38 ------7/9 ------7/9 -- -- 6.87 -- 7/9 -- 11.8 2.16 ------23.2 1.92 -- -- 7/8 -- 1.67 -- 7/8 -- 21.6 7/8 -- 19.8 2.20 7/8 1.94 7.90 7/9 27.7 1.66 1.85 7.79 1.06 1011 3.6812 43.8 --13 3.21 -- -- 10/25 2.25 -- 10/25 -- 0.77 -- 0.24 .54 -- .24 ------7/9 -- -- 7/9 2.61 -- -- 63.8 .71 1.46 ------ment (fig. 1) location measure- , square miles; ft Base-flow 2 Location description Road ence with Paradise Creek Swiftwater Creek confluence Road bridge ence with Forest Hills Run ence with Swiftwater Creek ence with Forest Hills Run ence with Paradise Creek Paradise Creek with Brodhead Creek Drive near Tannersville Paradise Creek at Devils Hole Devils Hole Creek above conflu- Paradise Creek upstream from Swiftwater Creek at Swiftwater Creek at Hulbert Hill 4Swiftwater Creek above conflu- 6.59Forest Hills Run above conflu- --Swiftwater Creek below conflu- Cranberry Creek above conflu- --Butz Run above confluence with --Paradise Creek above confluence Dry Sawmill Run at Skyview --Wolf Swamp Run at Confluence Pocono Creek at Wilke Road --Pocono Creek at Camelback Road 14 -- 15 8.65 9.32 7/8 -- -- 18.0 -- 2.73 ------5/2 5/2 11.6 12.0 1.34 1.29 ------Locations in downstream order, base flows measured, and subbasin yields for the Paradise Pocono Creek watersheds, Monroe Co (decimal Latitude/ degrees) longitude 41.098889/ 75.273611 41.053700/ 75.340800 41.128611/ 75.315278 41.128333/ 75.308333 41.101111/ 75.269722 41.093889/ 75.322500 41.100833/ 75.271944 41.101111/ 75.271944 41.101111/ 75.271389 41.100833/ 75.250556 41.078056/ 75.229722 41.070556/ 75.226111 41.078528/ 75.377000 41.059583/ 75.368083 41.061700/ 75.360200 Table 2. [Horizontal datum is North American Datum of 1927; mi 2000; May 2-3, 2001; and July 8-9, 2003. Streamflow Statistics for Monroe County, Pennsylvania 9 ) 2 /s/ 3 mi yield Sub- basin (ft /s) 3 (ft Base flow measured July 8-9, 2003 ment Paradise Creek locations Date of October 25-27, October measure- unty, Pennsylvania: ) 2 /s/ 3 mi yield Sub- basin (ft /s) 3 (ft Base flow measured May 2-3, 2001 Pocono Creek locations ment Date of measure- ) 2 /s/ 3 mi yield Sub- basin (ft , cubic feet per second per square mile; NA, not appropriate or indeterminable; --, no data] , cubic feet per second square mile; NA, 2 /s) 3 /s/mi 3 (ft Base flow measured October 25-27, 2000 Pocono Creek locations ment 10/26 5.65 .30 ------10/27 5.90 .54 ------Date of measure- ) 2 /s, cubic feet per second; ft 3 area (mi Drainage 25 22.227 10/2728 25.2 7.5429 10/26 2.90 .34 NA 10/26 10.3 5/2 10/26 1.13 .41 24.3 .39 .48 5/2 1.09 -- -- 31.0 -- 1.23 ------1617 9.3718 10/25 1.52 10/25 10.9 6.0120 10/25 0.64 .3721 11.6 6.47 .2422 -- 6.09 .59 10/25 18.8 -- -- 5/2 10/27 1.22 -- -- 15.6 7.11 .20 -- 1.43 .38 ------5/2 -- 5/2 -- -- 15.0 -- 19.4 ------1.29 1.03 ------ment (fig. 1) location measure- , square miles; ft Base-flow 2 Location description Road at Tannersville Road near Tannersville Road Golden Slipper Road with Coolmoor Run with Pocono Creek with Coolmoor Run near Tannersville at SR611 Tannersville Mill Run above Old RoadPocono Creek below Warner 24Bulgers Run above Learn Road 1.27Pocono Creek below Stadden 26 10/25Reeders Run above 2.34Rocky Run above Hunter Lake at .37 10/25 .29 .69 -- .29 ------Pocono Creek above confluence Coolmoor Run above confluence Pocono Creek below Confluence Pocono Creek at Sullivan TrailPocono Creek above Scot Run 19Scot Run above Scotrun Avenue 11.5Pocono Creek above SR715 at 10/27Pocono Creek at Tannersville 6.17 23 .54 19.0 5/2 10/25 15.3 5.97 1.33 .31 -- 5/2 -- 19.5 1.03 ------Locations in downstream order, base flows measured, and subbasin yields for the Paradise Pocono Creek watersheds, Monroe Co (decimal Latitude/ degrees) longitude 41.030528/ 75.303889 41.023389/ 75.303306 41.033944/ 75.310194 41.028778/ 75.315972 41.011889/ 75.319167 41.004833/ 75.314222 41.051200/ 75.317100 41.051583/ 75.338278 41.051333/ 75.338889 41.050889/ 75.336917 41.050750/ 75.321361 41.059861/ 75.316417 41.045583/ 75.310778 41.038806/ 75.309806 Table 2. [Horizontal datum is North American Datum of 1927; mi 2000; May 2-3, 2001; and July 8-9, 2003.—Continued 10 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania ) 2 /s/ 3 mi yield Sub- basin (ft /s) 3 (ft Base flow measured July 8-9, 2003 ment Paradise Creek locations Date of October 25-27, October measure- unty, Pennsylvania: ) 2 /s/ 3 mi yield Sub- basin (ft /s) 3 (ft Base flow measured May 2-3, 2001 Pocono Creek locations ment Date of measure- ) 2 /s/ 3 mi yield Sub- basin (ft , cubic feet per second per square mile; NA, not appropriate or indeterminable; --, no data] , cubic feet per second square mile; NA, 2 /s) 3 /s/mi 3 (ft Base flow measured Mean .36 1.09 1.76 Median .35 1.16 1.85 October 25-27, 2000 Minimum .11 1.01 .71 Maximum .64 1.43 2.73 Pocono Creek locations ment Standard deviation .12 .15 .55 Date of measure- ) 2 /s, cubic feet per second; ft 3 area (mi Drainage 3031 NA NA 10/2633 10/26 0.0534 4.06 -- .0535 10/26 36.2 -- 10/26 1.44 -- .8137 13.7 10/26 .35 --38 -- 40.7 .38 .32 10/26 ------1.8240 .40 10/26 16.0 ------1.17 .39 .20 ------10/27 -- .11 ------5/3 .33 ------41.3 -- .28 -- -- 1.01 ------ment (fig. 1) location measure- , square miles; ft Base-flow 2 Location description Golden Slipper Road Reeders Run Road Learn Road Barton Glen Road Run near Stroudsburg with Pocono Creek ite Road Rocky Run spring tributary above Rocky Run spring tributary below Rocky Run below Hunter LakeCranberry Creek above SR611 at 32Pocono Creek below SR611 near 2.14Laurel Lake Run above Beehler 10/26Pocono Creek at Rimrock DrivePocono Creek above Wigwam .80 36 0.37Wigwam Run above confluence 38.0Pocono Creek near Stroudsburg -- --Little Pocono Creek below Tan- 39 -- -- 44.0 -- 10/27 -- 15.2 -- 5/3 .35 40.5 -- 5/3 1.07 -- 45.3 -- 1.03 ------Locations in downstream order, base flows measured, and subbasin yields for the Paradise Pocono Creek watersheds, Monroe Co (decimal Latitude/ degrees) longitude 41.024028/ 75.298361 40.990861/ 75.256222 40.979111/ 75.223306 41.005028/ 75.313444 41.005750/ 75.315111 41.009528/ 75.304972 41.012000/ 75.290861 41.015333/ 75.289194 41.003500/ 75.280100 40.991556/ 75.255194 40.985722/ 75.226417 Table 2. [Horizontal datum is North American Datum of 1927; mi 2000; May 2-3, 2001; and July 8-9, 2003.—Continued Streamflow Statistics for Monroe County, Pennsylvania 11

Table 3. Observed streamflow statistics for continuous-record stations in Monroe County, Pennsylvania.

[USGS, U.S. Geological Survey; Q7,x, 7-day low-flow statistic for selected recurrence interval; Dx, flow-duration statistic equaled or exceeded selected percent of time; x-year BFLO, base flow for selected recurrence interval]

Streamflow at USGS streamflow-gaging station, in cubic feet per second Statistic 01439500 01440400 01442500 01447500 01447680 01448500 01449360 Mean monthly flow Oct. 124 74 318 118 33 2.9 64 Nov. 209 124 537 178 42 4.6 91 Dec. 263 169 722 213 51 5.9 125 Jan. 258 152 620 195 44 5.2 113 Feb. 271 158 657 197 43 5.0 114 Mar. 433 250 985 306 65 7.6 159 Apr. 429 249 978 353 75 9.2 157 May 303 179 697 252 55 6.6 125 June 200 115 451 167 45 4.3 101 July 128 58 254 107 28 2.8 65 Aug. 98 43 240 90 22 2.3 52 Sept. 94 56 250 90 27 2.2 57 Mean annual flow 234 135 558 189 45 4.9 102 Q7,2 18 13 79 24 7.4 .8 24 Q7,5 10 8.9 57 16 4.7 .5 18 Q7,10 7.4 7.3 48 13 3.7 .4 15 Q7,20 5.8 6.2 42 11 3.1 .4 13 D99 8.8 7.7 49 14 4.2 .1 15 D95 17 13 72 23 7.4 .4 22 D90 27 17 94 33 10 .8 28 D80 52 30 144 54 16 1.4 38 D70 83 47 204 77 21 2.0 49 D60 121 65 269 102 26 2.6 61 D50 161 85 349 130 32 3.2 75 D40 209 109 449 162 39 4.0 92 D30 269 142 583 203 48 5.2 114 D20 362 193 796 267 63 6.8 145 D10 531 301 1,230 399 91 9.8 202 D5 719 432 1,760 559 130 15 275 D1 1,270 887 3,410 1,090 244 32 510 Mean annual base 153 83 321 121 30 3.3 71 flow 2-year BFLO 157 84 325 122 30 3.4 73 5-year BFLO 125 68 262 101 24 2.7 59 10-year BFLO 110 61 232 91 20 2.4 52 25-year BFLO 95 54 203 80 17 2.1 45 50-year BFLO 85 49 186 74 16 1.9 41 All stations Maximum 1,270 887 3,410 1,090 244 32 510 3,410 Minimum 5.8 6.2 42 11 3.1 .1 13 .1 12 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania ) 2 /s, cubic feet (R 3 Adjusted coefficient of determination Residual standard error in Monroe County, Pennsylvania. 01449360 Log 01448500 indicates statistic predicted or observed as appropriate to equation; ft indicates statistic predicted or observed Log s r 01447680 Log 01447500 Log ) ) /s) 3 (ft 2.0971 0.9206 s s 01442500 Log ) ) ) ) ) )(01440400 )(01440400 Continuous-record index station(s) ) ) ) ) ) 1.4896 s 1.1343 01440400 -1.0838 0.87306 1.0254 0.85071 0.98443 s s s s s 0.59265 index stations -0.36102 0.75311 0.82561 0.64020 s s s s Log Regression coefficients for continuous-record stations tested as index 01439500 = 0.00116(01442500 == 0.114(01439500 = 1.46(01439500 = 1.60(01440400 = 0.0391(01439500s = 4.31(01439500s = 0.126(01442500 = 1.28(01440400 = 0.432(01439500 1.69(01440400 = 0.400(01449360 (A) (b) (c) (d) (e) (f) (g) (h) Log units Percent

.68574 -1.0838.16532.20316 2.0971 -.36102.63422 -- .9206 --.10733 .59265 .75311.22781 ------.82561 -- -- .64020 ------.10 ------23.3 .05 -- -- .03 11.6 .96 -- .10 6.9 -- .96 .05 23.3 .98 .11 11.6 .90 25.7 .98 .91 s -.94344 .87306 ---.89884-.36495 -- ---.39796 .85071 ------1.0254 ------.20 ------48.6 -- -- .04 .85 0.98443 .13 9.2 .04 30.6 .99 9.2 .92 .97 Intercept Log -2.9365 ---1.4081 -- 1.1343 1.4896 ------0.11 -- 25.7 0.96 .17 40.7 .78 = 0.206(01439500 s s s s s s s s s s s s /s) 3 (ft Regression coefficients and equations for predicting 7-day, low-flow recurrence-interval statistics at partial-record stations 01440300 01440500 01440272 01440485 01440800 01441500 01442600 01442700 01449355 01441000 01441495 01440250 station statistic Log of station 01440250 01440272 01440300 01440485 01440500 01440800 01441000 01441495 01441500 01442600 01442700 01449355 statistic at Predicted partial-record Equations for predicting 7-day, low-flow statistics at partial-record stations using from continuous-record partial-record Log Log Log Log Log Log Log Log Log Log Log Log Table 4. station numbe in table 1; --, not signiﬁcant at the p<0.05 level; with 014 are station numbers shown [8-digit numbers beginning per second] Comparison of Predicted and Observed Streamflow Statistics for Continuous-Record Stations 13

Although the Stedinger and Thomas (1985) methodology Differences in Predicted and Observed Streamflow was developed for predicting low-flow recurrence-interval sta- Statistics for Continuous-Record Stations tistics, the equations resulting from this method (table 4) were used to predict all the statistics shown in table 3 for the partial- Although the Stedinger and Thomas (1985) methodology record stations. The predicted statistics for the partial-record stations are shown in table 5. The same descriptions and acro- was developed specifically for predicting low-flow recurrence- nyms discussed above for table 3 apply to the statistics in interval statistics at partial-record stations, the equations in table 5. table 6 were used to predict the previously discussed 36 statis- The range between the maximum and minimum statistics tics for the 7 continuous-record stations. An example of the for each station in table 5, as exemplified by 212 and 0.3 ft3/s relation between observed and predicted statistics for Lehigh for Shawnee Creek at Shawnee, reflect smaller absolute differ- River at Stoddartsville is shown in figure 5. Good agreement ences than in table 3, but approximately the same range in order between the predicted and observed statistics is visually evi- of magnitude. The smaller range in D1 values (flows equaled or dent. exceeded 1 percent of the time), from 439 to 57 ft3/s, for all stations reflects a smaller range of drainage areas (from 65.3 to 4.58 mi2) for the partial-record stations than for the continuous- record stations.

Comparison of Predicted and Observed Streamflow Statistics for Continuous- Record Stations

The seven continuous-record stations used in the analyses for this study also were treated as if each was a partial-record Figure 5. Observed and predicted streamflow statistics for Le- station similar to Wilson (2000). The test was used to determine high River at Stoddartsville, Pa. how well the Stedinger and Thomas (1985) methodology predicted statistics compared to those observed for the continuous- Predicted statistics for the seven continuous-record sta- record stations and to provide quantitative results on how well tions using the equations in table 6 are shown in table 7, along the methodology predicted high- and intermediate-flow statis- with the absolute percent differences from the observed statistics that were based on low-flow coefficients and equations. tics. The predicted statistics range from a maximum of about 2,660 ft3/s (flow equaled or exceeded 1 percent of the time, D1) to a minimum of 0.3 ft3/s (lowest average flow expected for Regression Analyses of Continuous-Record Station 7 consecutive days every 20 years, Q7,20). Data The mean difference of 9 percent and the median difference of 7 percent of all predicted statistics from all observed Regression coefficients and equations for continuous- statistics for the continuous-record stations do not show a large record stations tested as indexes for predicting 7-day low-flow disparity. The small differences may be a function of the previ- statistics at the other continuous-record stations are shown in ously mentioned plotting and correlation procedure and the best table 6. The only continuous-record station not included in a relations discussed above. The mean differences indicate by best relation as an index was Dilldown Creek near Long Pond, their small magnitudes that there may be a consistent relation the station with the smallest drainage area (2.39 mi2). This between low-flow statistics and higher-flow statistics at a sta- result was similar to the Wilson (2000) finding that stations tion and that the Stedinger and Thomas (1985) methodology with larger drainage areas tended to have better predictive capa- may be appropriate for predicting high- and intermediate-flow bilities than stations with smaller drainage areas. statistics for partial-record stations. The maximum difference All seven relations shown in table 6 had standard errors of (123 percent) and the second highest difference (52 percent) in less than 30 percent and coefficients of determination (R2) observed and predicted statistics both occurred for the Dilldown greater than or equal to 0.89. These results indicate the relations Creek near Long Pond station and were not for high-flow but are good fits for predicting 7-day, low-flow recurrence-interval for low-flow statistics. Those high values are mathematical by- statistics at the respective continuous-record stations. Although products caused when the differences in observed and predicted only 2 of the 12 partial-record stations had 2 significant index statistics are much greater than their averages, artifacts from the stations, 4 of the 7 continuous-record stations treated in the very low flows that occur at small drainage-area stations like same manner had multiple indexes. The Dilldown Creek near Dilldown Creek. The actual absolute difference between the Long Pond station was the only station to have three index sta- observed and predicted statistics for those two highest percent tions in its best relation. differences was only 0.3 ft3/s. 14 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania led or exceeded selected percent of time; x-year BFLO, base Streamflow at USGS partial-record gaging station, in cubic feet per second 01440250 01440272 01440300 01440485 01440500 01440800 01441000 01441495 0144150001442700 01442600 01449355 Predicted streamflow statistics for partial-record stations in Monroe County, Pennsylvania. Statistic Oct.Nov.Dec.Jan.Feb. 6.2Mar. 13Apr. 21May 9.2 17 15June 18 23July 33 7.7Aug. 19 33 12 19Sept. 20 15 31 14 10 15 31 18 15 4.4 22 22 41 23 4.1 14 20 4.3 23 60 5.4 20 17 76 3.8 26 9.3 12 6.9 70 17 26 7.9 72 22 22 102 6.2 75 17 6.0 102 21 102 11 22 117 79 38 9 41 12 57 116 38 69 34 119 26 93 157 27 45 33 16 156 80 68 9.6 84 127 127 88 7.1 26 100 126 6.8 81 76 41 122 84 89 65 49 122 27 64 58 49 33 37 75 51 93 31 45 75 32 24 64 42 37 34 58 43 56 29 46 58 36 39 42 27 59 42 47 21 58 21 35 23 46 19 22 38 24 20 21 Mean monthly flow Mean annual flowQ7,2 14Q7,5Q7,10Q7,20 16D99D95 .8D90 13 .5D80 .4D70 2.1 .3 19D60 1.4 1.2D50 .4 1.4 1.0D40 .7 64 1.0D30 .8 1.4 1.9 .5D20 5.6 2.1 3.2 .4 19D10 2.2 4.6 4.8D5 3.6 .8 4.1 11 7.1 1.4 5.5 109 3.8 10 2.0 8.2 7.2 15 3.6 7.1 4.4 9.3 1.0 24 5.6 5.4 6.2 72 12 6.0 46 7.5 .5 16 8.0 7.4 10 .3 24 11 79 10 22 13 .2 73 12 12 36 16 21 15 13 .5 14 11 56 29 1.0 20 11 1.6 45 16 37 27 7.9 3.5 16 19 45 6.6 23 11 36 5.9 30 22 5.7 39 55 9.0 45 29 7.6 67 6.4 6.2 12 59 9.2 36 5.1 84 12 5.6 17 74 117 38 18 2.9 22 6.9 2.2 11 88 154 26 8.7 31 13 1.7 102 48 34 6.3 21 119 5.4 2.7 68 45 31 141 4.8 9.0 4.7 58 178 7.1 40 6.7 12 75 6.2 5.7 212 50 102 8.7 19 4.9 10 158 62 26 15 77 226 5.8 99 33 8.4 142 20 11 41 24 192 14 50 29 65 90 18 34 116 23 40 49 28 65 34 82 42 54 74 101 USGS, U.S. Geological Survey; Q7,x, 7-day low-flow statistic for selected recurrence interval; Dx, flow-duration equa flow for selected recurrence interval] Table 5. [ Comparison of Predicted and Observed Streamflow Statistics for Continuous-Record Stations 15 All stations led or exceeded selected percent of time; x-year BFLO, base Streamflow at USGS partial-record gaging station, in cubic feet per second 6.3 9.4 9.2 14 45 12 85 41 49 31 29 27 01440250 01440272 01440300 01440485 01440500 01440800 01441000 01441495 0144150001442700 01442600 01449355 Predicted streamflow statistics for partial-record stations in Monroe County, Pennsylvania.—Continued Statistic 2-year BFLO5-year BFLO10-year BFLO25-year BFLO 6.450-year BFLO 4.6 3.9 9.3 3.2 7.7 2.8Maximum 7.0Minimum 9.4 6.4 7.7 5.9 6.9 14 212 6.1 12 5.5 12 .3 136 45 11 38 11 35 1.0 58 12 32 30 9.3 8.1 .4 57 86 6.8 75 6.0 70 265 3.8 64 42 34 60 30 130 6.2 26 50 42 24 298 38 .2 34 32 32 26 439 11 24 21 29 348 25 19 23 5.7 22 27 189 20 22 5.6 20 17 130 15 1.7 185 4.7 439 4.9 .2 D1Mean annual base flow 212 136 58 57 265 130 298 439 348 189 130 185 USGS, U.S. Geological Survey; Q7,x, 7-day low-flow statistic for selected recurrence interval; Dx, flow-duration equa flow for selected recurrence interval] Table 5. [ 16 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania ) 2 /s, cubic feet (R 3 Adjusted coefficient of determination Residual standard error ns (treated as partial-record stations) in 01449360 Log 01448500 indicates statistic predicted or observed as appropriate to equation; ft indicates statistic predicted or observed Log s r 01447680 Log ) 0.48439 s 01447500 Log )(01449360 ) ) ) 01442500 0.37486 s 0.45264 0.81666 Log s s 0.47369 /s) s 3 (ft )(01447680 01440400 )(01442500 )(01449360 ) ) )(01447680 ) Log 0.18917 s 0.55203 0.25001 Continuous-record index station(s) stations s s 1.0778 0.84948 0.88924 0.31613 s s s s Regression coefficients for continuous-record stations tested as index 01439500 = 0.362(01439500 = 8.32(01440400 = 2.52(01440400 = 0.284(01447500 = 0.0445(01440400 = 3.64(01440400 (A) (b) (c) (d) (e) (f) (g) (h) Log units Percent .92013.40183 -- --.56051 .84948 -- .88924 -- -- .31613 ------.47369 ------.06 .10 13.9 .09 23.3 20.9 .97 .92 .92 -.44118 0.55203-.54615 -- -- 0.45264 ------0.25001 ------.06 0.81666 13.9 .12 .98 28.2 .89 0.09679 -- 1.0778 ------0.10 23.3 0.96 -1.3515 -- .18917 -- -- 0.37486 -- .48439 .08 18.6 .96 Intercept Log = 1.25(01440400 s s s s s s s

s /s) 3 Regression coefficients and equations for predicting 7-day, low-flow recurrence-interval statistics at continuous-record statio (ft statistic Log of 01439500 01440400 01447500 01447680 01442500 01448500 01449360 station 01439500 01440400 01442500 01447500 01447680 01448500 01449360 stations (treated as partial-record stations) using statistics from continuous-record index record station Equations for predicting 7-day, low-flow recurrence-interval statistics at continuous-record statistic at Predicted partial- partial-record Log Log Log Log Log Log Log Table 6. Monroe County, Pennsylvania. station numbe in table 1; --, not signiﬁcant at the p<0.05 level; with 014 are station numbers shown [8-digit numbers beginning per second] Comparison of Predicted and Observed Streamflow Statistics for Continuous-Record Stations 17 /s % 3 l; Dx, flow-duration statistics y, Pennsylvania. /s % ft 3 /s % ft 3 /s % ft 3 /s % ft 3 Predicted streamflow and percent differences for continuous-record streamflow-gaging stations /s % ft 3 /s, cubic feet per second; %, percent difference from observed; Q7,x, 7-day low-flow statistics for selected recurrence interva 3 01439500 01440400 01442500 01447500 01447680 01448500 01449360 /s % ft 3 ft

Predicted streamflow statistics and percent differences from observed for continuous-record stations in Monroe Count Statistic Oct.Nov.Dec.Jan.Feb. 129 225Mar. 315Apr. 4May 281 8 18June 293 70 480July 119 8 154 478Aug. 8 10 335Sept. 5 143 4 11 208 9 150 10 234 322 99 499 6 232 72 4 650 5 164 96 7 25 1 594 7 31 107 7 11 614 9 2 906 116 65 183 4 242 903 54 7 7 682 8 11 2 54 220 3 13 23 8 468 227 2 342 262 3 12 28 203 341 41 56 4 14 11 254 3 16 254 17 50 3 172 2 9 51 1 75 93 2 14 72 2.8 3 17 77 4.0 5.3 14 14 58 90 23 4 14 10 4.7 2 44 4.7 6 28 10 7.0 0 74 22 118 98 2 6 7.4 8 107 1 15 24 0 5.5 5 22 7 107 150 4.3 18 6 13 2.5 161 2.0 6 1 125 6 10 16 2.3 2 99 0 64 5 52 2 2 62 1 8 Mean monthly flow Mean annual flowQ7,2 247Q7,5Q7,10 5Q7,20D99 129 20D95 13D90 10 11 5D80 26 8.3D70 30D60 537 11 13 35D50 20 8.3D40 25 26 6.5 4 0D30 15 5.3 49 7 12D20 79 2 198 16 7.0 112D10 73 6 12 150 52 43 5 9 5 17 196 7 38 8 30 8 261 7 9 11 46 363 6 10 3 47 46 64 25 586 3 1 74 85 17 14 0 2 110 4 12 2 92 10 1 4 142 150 2 0 6 7 192 219 1 9 15 290 2 289 4.4 0 4 25 8.5 362 0 7 448 10 5.7 4.7 11 4 7 31 14 560 3.9 52 7 4 19 24 727 1,061 0 77 104 23 103 5 5 4 4 131 .7 15 9 164 8 1 2 .5 .4 1 18 207 13 10 .3 1 15 404 272 1 0 0 5 20 29 26 2 4 21 .4 6 1 33 2 15 12 41 123 4 11 0 13 .7 51 2 .9 97 18 22 67 1.4 52 4 17 14 1.9 12 7 2.4 0 6 6 3.1 21 9 5 3.8 7 26 4.8 4 40 5 4 9.3 6.3 52 64 8 6 76 4 5 7 91 6 109 4 187 137 2 1 5 8 6 USGS, U.S. Geological Survey; ft equaled or exceeded selected percent of time; x-year BFLO, base flow for recurrence interval] Table 7. [ 18 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania % All stations /s % 3 l; Dx, flow-duration statistics y, Pennsylvania.—Continued /s % ft 3 /s % ft 3 /s % ft 3 /s % ft 3 Predicted streamflow and percent differences for continuous-record streamflow-gaging stations /s % ft 3 /s, cubic feet per second; %, percent difference from observed; Q7,x, 7-day low-flow statistics for selected recurrence interva 3 01439500 01440400 01442500 01447500 01447680 01448500 01449360 /s % ft 3 146 4 79 5 355 10 128 6 31 2 2.9 13 74 4 ft Predicted streamflow statistics and percent differences from observed for continuous-record stations in Monroe Count Statistic D5D1Mean annual base flow 866 1,880 19 39 403 743 7 18 1,442 2,657 20 25 1,055 556 3 0 266 136 9 4 25.9 13.2 21 13 420 248 19 10 2-year BFLO65-year BFLO10-year BFLO 14825-year BFLO 11850-year BFLO 105 6 92 6 5 83 80 3 63 3 55 5 50 7 10 45 359 9 300 273 10 9 14 246 16 130 227 19 107 98 6 20 6 88 7 80 31 9 25 22 8 5 5 19 10 17 2.9 11 2.3 14 2.0 8 13 17 1.7 74 1.6 19 62 55 18 1 49 5 6 46 9 12 MeanMedianMaximumMinimum 12 39 7 0 7 23 7 0 9 25 8 0 23 6 5 0 24 8 6 0 123 15 10 0 22 7 123 6 9 0 7 0 USGS, U.S. Geological Survey; ft equaled or exceeded selected percent of time; x-year BFLO, base flow for recurrence interval] Table 7. [ Limitations of the Investigation and Statistics 19

Limitations of the Investigation and Relative subbasin yields for the Paradise and Pocono Creek watersheds were consistent during each measurement Statistics period with few exceptions. One exception was a losing reach along the Pocono Creek main stem. Another exception was the The study and the resulting statistics are limited to streams high subbasin yield for Swiftwater Creek in the Paradise Creek in Monroe County, Pa. The subbasin yields calculated from the watershed that probably reflects surface-water discharges from three sets of miscellaneous measurements are relative to those treatment facilities upstream. periods and flow regimes and may not reflect the full range of A suite of 36 streamflow statistics were computed for 7 hydrologic conditions in the Paradise and Pocono Creek water- continuous-record stations and predicted for 12 partial-record sheds. The methodology proposed by Stedinger and Thomas stations in Monroe County, Pa. The statistics for each station (1985) for predicting low-flow recurrence-interval statistics ranged in magnitude from a high-flow duration equaled or was the only one used for predicting statistics at partial-record exceeded only 1 percent of the time (D1) to the 7-day, 20-year stations; other methods briefly mentioned in the previous stud- recurrence-interval low flow (Q7,20) or the low-flow duration equaled or exceeded 99 percent of the time (D99). Low stan- ies section of this report may have resulted in more accurate sta- 2 tistics. The Stedinger and Thomas (1985) methodology for pre- dard errors and high coefficients of determination (R ) indicate dicting statistics does not apply to stream locations having good agreement in using intermittent measurements at partial- intermittent flow. The standard errors in percent and the coeffi- record stations and concurrent daily mean flows at continuous- cients of determination (R2) in tables 4 and 6 are diagnostics record stations to predict low-flow recurrence-interval statistics reflecting the expected errors in the predicted statistics using the for the partial-record stations. selected methodology. The predicted statistics for the partial- The study and the resulting statistics are limited to streams record stations that had only six usable measurements for the in Monroe County. All the observed, predicted, and subbasin- analyses may have more error than indicated in table 4. All the yield statistics are estimates affected by time and measurement observed, predicted, and basin-yield statistics are estimates errors. The comparison of predicted and observed statistics for affected by time and measurement errors. the continuous-record stations indicates the prediction methodology used in the study may have application potential for predicting high- and intermediate-flow statistics, not just for low- flow statistics as done in previous investigations. Although all Summary and Conclusions the statistics contain error, as discussed herein, these statistics do constitute the results needed by Delaware River Basin water- Streamflow statistics are needed in the Paradise and shed groups for planning purposes and input for ground-water Pocono Creek watersheds and in surrounding parts of Monroe modeling. County, Pa., to quantify surface-water resources and as input to ground-water models. Subbasin yields for the Paradise and Pocono Creek watersheds also are needed for various purposes. Acknowledgements In order to fulfill these objectives, the U.S. Geological Survey, the Delaware River Basin Commission, and the Brodhead Review and suggestions by Edward Koerkle, Kim Otto, Watershed Association cooperated in a study to determine the Marla Stuckey, Curtis Schreffler and John Wilson, all of the needed streamflow statistics. U.S. Geological Survey, are very much appreciated. Edward Monroe County is in the Pocono Mountains of northeast- Koerkle deserves special credit in that his development of the ern Pennsylvania. Surficial geology includes glacial deposits, plotting and correlation procedure mentioned above greatly sandstones, conglomerates, siltstones, shales, and small reduced the time which would have been expended on an other- amounts of carbonate rock. Areas where porous glacial deposits wise tedious task and improved the accuracy of the predicted are connected to the water table typically yield higher stream statistics by helping eliminate streamflow measurements made base flows per unit of drainage area during dry periods than outside base-flow conditions. nonglaciated parts of Pennsylvania. Different approaches have been used previously by researchers to predict low-flow statistics at locations in Penn- sylvania and other states without daily mean flow data. For this Selected References study, observed streamflow statistics for continuous-record stations were computed from daily mean flows retrieved from U.S. Berg, T.M., 1975, Geology and mineral resources of the Brod- Geological Survey databases. Predicted statistics for the partial- headsville quadrangle, Monroe and Carbon Counties, record stations were obtained by correlating intermittent mea- Pennsylvania: Pennsylvania Geological Survey, 4th ser., surements made at partial-record stations with concurrent daily Atlas 205a, 60 p., 3 pls. mean flows from seven continuous-record stations operated in Berg, T.M., Sevon, W.D., and Bucek, M.F., 1977, Geology and Monroe County. mineral resources of the Pocono Pines and Mount Pocono 20 Streamflow Statistics for the Paradise and Pocono Creek Watersheds, Monroe County, Pennsylvania

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